Air filter frame



July 18, 1961 c. s. REID AIR FILTER FRAME;

Filed July 9, 1958 INVENTOR.

CHARLES S. REID Wpf A ORNEYS.

United States Patent 2,992,702 AIR FILTER FRAME Charles 8. Reid, New York, N.Y., assignor to Continental Gan Company, Inc., New York, N.Y., a corporation of New York Filed July 9, 1958, Ser. No. 747,438 2 Claims. (Cl. 183-49) The invention relates to a frame to hold air filtering material such as spun glass, for filter elements such as those now widely used in air conditioning units for buildings and homes.

According to my invention the filter frame comprises a body made of complementary half sections, each of which consists of a single sheet of paperboard and has a fiat perforate face and two opposed tubular edges of generally rectangular form. The two sections are joined together with their flat perforate faces in spaced parallel relation and with the opposed tubular edges of one section arranged at right angles to those of the other section. The tubular edges of each section are secured to the inside edges of the fiat perforate face of the other. These tubular edges are constituted by folded and glued edge portions of the sheet. I have discovered that when the individual sections, or components, are constructed in a fiat folded form in which the two opposed tubular edges are collapsed inwardly, erection of the tubular edges will bias the fiat perforate face inwardly. What happens is that the face takes the form of an inward bow. The result of this is that after the filter element has been inserted, the perforate face of the frame springs firmly against the face of the filter element. Another advantageous result is that the tubular edges themselves are likewise biased inwardly to close with the edges of the filter element. This action is further assisted by the tendency of the inwardly bowed faces of the frame to pull the opposed tubular edges together, so that in the completed assembly the frame snugs tightly against both the faces and edges of the filter element. The inward bias of the faces and edges of the frame is produced by the fight of the paperboard stock, and this action is enhanced by the fact that the fight of the stock occurs at each of the several corners of the tubular edges of the complementary frame components.

With reference to the drawing, I here describe the best mode contemplated by me for carrying out my invention.

FIG. 1 is an end elevational View of one of the frame components as constructed in flat folded form.

FIG. 2 is an end elevational view of the same frame component with the tubular edges erected for assembly with the filter element.

FIG. 3 is a perspective view illustrating the final step in assembling the component with another component of like construction.

In these views we see an air filter frame of paperboard and the like comprising a body made of complementary half sections, each of which consists of a single sheet of paperboard and has a fiat perforate face 4 and two opposed tubular edges 5 of generally rectangular form constituted by folded edge portions of the sheet. The perforate faces of the frame form a lattice or screen which holds the filter material while permitting relatively free passage of air through the filter. Preferably the paperboard is scored at the several lines of folding, and the edges of the sheet glued to the backs of face panels 4 as at 8. The two sections are joined together with their fiat perforate faces in spaced parallel relation and the opposed tubular edges of one section arranged at right angles to those of the other section, and the tubular edges 2,992,702 Patented July 18,, 1961 ICC of each section are secured to the inside edges of the flat perforate face of the other, i.e. over the area lndlcated by the stippling at 6 in FIG. 3. For this purpose a suitable adhesive may be applied to the edges of the tubes. If desired a pressure sensitive adhesive coating may conveniently be used, such as a suitable adhesive coating of the kind which will produce adherence only upon contact between two similarly coated surfaces. Or in some cases a thermoplastic adhesive may be preferred.

FIG. 2 illustrates the effect of erecting the tubular edges of one of the frame components which has been constructed in a flat folded form in which these edges are collapsed inwardly. Notice the inward bowing of the face 4 of the component as seen in this view. Insertion of the filter element 7 as in FIG. 3 flattens out the face 4 and tends to square up the edges 5 of the frame component, retaining an inward bias of the face 4 and the tubular edges 5 themselves being biased inwardly in the directions indicated by the arrows a to close with the edges of the filter element. In the upper part of FIG. 3 we again see the inward biasing action, this time with reference to the second of the two frame components. As the second component is pressed downwardly into its assembled relation with the first component, its face flattens out and the edges of the tubes 5 of each component are secured to the inside edges of the face 4 of the other component. In the completed assembly, by reason of the special biasing action I have described, the frame snugs tightly against both the faces and edges of the filter element.

The terms and expressions which I have employed are used in a descriptive and not a limiting sense, and I have no intention of excluding such equivalents of the invention described as fall within the scope of the claims.

I claim:

1. The combination of a filter element enclosed by a frame therefor, said frame being formed of paperboard and the like and comprising a body made of identical complementary half sections, each of such sections being formed of a single sheet of paperboard and having a flat perforate face, the ends of each face terminating in two opposed tubular edges of generally rectangular form, said flat perforate face of each section having a length substantially equal to the width of the other perforate face such that the tubular edges of each section lie within the area of the perforate face of the other section, opposed inner side edges of each perforate face being adhesively secured to the corresponding opposed tubular edges of the other section, the opposed tubular edges of each section extending between the ends of and substantially perpendicularly to the corresponding tubular edges of the other section, said flat perforate faces being in spaced substantially parallel relation with said filter element enclosed therebetween, the tubular edges of both sections having a built-in inward bias in abutment with the edges of said filter element.

2. The combination of a filter element enclosed by a frame therefor, said frame being formed of paperboard and the like and comprising a body made of identical complementary half sections, each of such sections being formed of a single sheet of paperboard and having a flat perforate face, the ends of each face terminating in two opposed tubular edges of generally rectangular form, said flat perforate face of each section having a length substantially equal to the width of the other perforate face such that the tubular edges of each section lie within the area of the perforate face of the other sections, said tubular edges. each having a flat adhesive: engaging portion lying in a plane substantially parallel to its perforated face, opposed inner side edges of each perforate face being adhesively secured to the corresponding op- References Cited in the file of this patent UNITED STATES PATENTS Slayter et a1 May 30, 1939 Stensgaard May 27, 1947 Cooper Nov. 22, 1949 Kaiser Feb. 21, 1956 Vander Lugt July 24, 1956 Samsing Sept. 9,1958 

